Zoladex plus tamoxifen versus Zoladex alone in pre- and peri-menopausal metastatic breast cancer.

Phase II studies examining the endocrinological and clinical efficacy of Zoladex and Zoladex plus tamoxifen have been examined in pre- and peri-menopausal women with advanced breast cancer. No adverse endocrinological interaction between the drugs have been observed. Although a higher proportion of static disease was observed with the combination of the drugs, which possibly occurred at the expense of partial remissions, the time to disease progression was extended in women who received Zoladex plus tamoxifen. Remissions were primarily restricted to patients whose tumours were ER positive. Only occasional responses were seen in ER negative disease. This was especially evident where the ER negative tumours were EGF-R positive and showed high rates of cell proliferation.